Feral druids have had it rough. From being a class that could only barely tank in vanilla WoW, to the best 5-man tank in early TBC, to the worst raid-tank in end-game, they've come a long way.

One of the greatest changes to druids' tanking capabilities comes not from a change to the druid class, but from the combat system as a whole. Crushing blows, the Feral druid's worst enemy, is being removed as a staple of bosses. Crushing blows were the greatest source of physical damage to druids in TBC, and now that it is going to be removed, druids will reap the benefits. Druids have long been the greatest Effective Health tanks, but they haven't been able to put it to good use, mainly due to crushing blows.

This change was needed—badly. Druids in raids are by far the worst tank. They cannot use health potions, healthstones, and armor potions—without at least taking a huge risk. The risk can be mitigated by timing the shift correctly, but it should not be underestimated. Druids also hit a scaling problem—their main source of physical mitigation (in fact, their sole source of physical mitigation) is armor. Armor has a cap of 75% mitigation. Once druids hit it—and they will—they have no other way of increasing their mitigation. They have no block, so cannot stack block value.

Druids' strongest ability in raids is their versatility: Being able to fill both a tanking role and a DPS role in the same encounter (although with reduced capabilities), and being able to fill a full tanking or DPS role depending on the encounter. They can also add sporadic off-healing, though this is not really a good use of them. Whether or not this versatility will remain in WotLK, and whether or not it even comes into play, remains to be seen.
I'll go over the released talents and spells in note-form and what I think of them.

Talents:

* Feral Instinct has had its contribution to base threat stripped, just as Defiance did for warriors. I have looked around, but I cannot find any information whether or not that increase was made baseline; I think it will be, but I'm hesitant to assume. In the place of the threat boost is a boost to Swipe's damage. While nice, it is not required, and makes the talent significantly less desirable.
* Faerie Fire (Feral) replaces Feral Charge in the 3rd tier.
* Predatory Strikes gets 20% extra AP from the druid's weapon; a good threat boost to a weak talent.
* Feral Charge has been moved to the 5th tier, and now also allows for a charge in Cat Form—quite a significant change. In Cat Form, the immobilization effect has been changed to a daze effect, and rather than "charge" the enemy, you "leap behind them".
* Nurturing Instinct is getting a small nerf; from 100% agility to 70% agility. I don't really see the point of it, but I guess it could be a PvP-directed change.
* Primal Precision is the first completely new talent. It gives 10 Expertise skill and refunds 80% of the energy cost of a missed finishing move. A strong talent, both for tanking and DPS, though it's primary benefit is for Cat Form.
* Survival of the Fittest is possibly the most important of the changed talents, as it has had its contributions effectively doubled—making Feral druids crit-immune strictly from talents, assuming the chances to crit for bosses aren't changing.
* Primal Tenacity has changed; from having a 15% chance to resist Fear and Stun effects, it now reduces the duration of Fear effects by 30%, and reduces all damage taken while stunned by 30%. Previously, this talent was very lack-luster due to Predatory Instincts, as PI has the same chance to resist AoE effects -- and most fear effects are AoE. The two didn't stack. Now, though, the talent seems worth putting points into.
* King of the Jungle is the second new talent, and while it has a good, solid boost to threat generation while Enraged, the primary benefit of this talent is the energy addition to Tiger's Fury. 60 energy on-demand (even on a 30 second cooldown) is a huge boost to DPS. Tiger's Fury has also been significantly changed; more on that in the skills section.
* Infected Wounds is the next talent, and it has a massively important ability: Attack speed reduction. 10%, stacks to 5—more than double that of Improved Thunder Clap. I have not seen any classes with a greater attack speed reduction benefit; assuming this stands, it will be a powerful addition to the druids' arsenal, whether they are tanking or DPSing.
* Improved Mangle is a good talent, with a solid threat boost—reducing the CD of Mangle—and a half-decent energy reduction on the talent as well.
* Rend and Tear, on the other hand, is lack-luster. The threat increase for bears is just not worth the talent points, considering the bloat that has been introduced elsewhere in the tree, and while the boost to Shred is good, the change to Ferocious Bite is almost strictly a grinding change; cats use Rip in raids, not FB. I will only put points here if I do not have anywhere else to put them.
* The crowning jewel of the new Feral tree is Berserk, an utterly amazing must-have talent. It not only acts as a panic button by increasing your health by 30% while tanking, it also adds AE-effects to Maul and Mangle similar to Swipe. Cat Form has a somewhat lesser benefit, but it is still a good addition to their DPS. The talent is also strong in PvP with the removal of CC-effects.
* Omen of Clarity, a talent that has long belonged in the Feral tree, now properly fits into the Restoration tree. It is now passive, and seemingly procs on all spells and attacks. The only true boost to Ferals here is that it's passive, but if OoC can proc on healing spells, it will make off-healing quite a bit easier for Feral druids.

Also worth mentioning is Master Shapeshifter, which is a somewhat decent talent—except it is in the Restoration tree, and has Natural Shapeshifter as a prerequisite. Still, it's a good addition if you are going that deep into Restoration.

Skills:

* Tiger's Fury is the first change on the Feral druids' skill list. The energy requirement is completely removed, and it has received a 30-seconds cooldown. It goes from being a lackluster skill to being a very important one, especially in compunction with the talent King of the Jungle, which gives it a 60-energy increase when used.
* Frenzied Regeneration is seeing a change. Rather than having a fixed rage-to-health ratio, it now scales with maximum health. It also only has one rank. This is both good and bad—at lower levels, it will mean less health regenerated, but at higher levels, it will mean much, much more. 10 rage grants 3% health, meaning it can now heal for a maximum of 30% of your health, if you have 100 rage to burn. I am personally very pleased that this is getting changed.
* The first non-talent addition to their (Feral) skill list is the Cat Form ability Savage Roar, a finishing move that increases attack power by 25% for 9-21 seconds (based on combo points).

Those are the changes to skills I've been able to find. Of course there are also new ranks to all significant Feral skills—in fact, there are two for each primary ability (Mangle, Maul, Lacerate, Swipe, and Demoralizing Roar for bears; Mangle, Rip, Tiger's Fury, Ferocious Bite, Rake, Ravage, and Shred for cats).

EDIT: I just saw some very interesting news on the Druid forums.

"We do, however, intend to allow Druids to be able to use items and enchants with procs in forms, which I believe will work in the next beta build (don't hold me to it though)." --Koraa, Class Designer
Items and enchants with procs in forms? Wow. That's HUGE. Mongoose for druids. Executioner. VERY exciting. Depending on how you interpret the wording, this could mean potions and healthstones -- though it could also simply mean "items with procs". We'll have to wait and see how this plays out.

Thoughts on druids' role in raids:
With the very significant change on crushing blows, druids become the physical damage specialist. Druids have massive advantages with regards to physical Effective Health over all other tanks. In addition, druids retain their versatility in single and multiple encounters. Assuming crit-mechanics have not changed, druids are now crit-immune solely from talents. This represents a paradigm shift; druids no longer require Defense or Resilience to tank. This increases their versatility by leaps and bounds, as DPS gear shares many needs with tanking gear: Agility is the strongest druid stat; it increases attack power, crit and dodge for cats, and crit and dodge for bears. Stamina is the most important tank stat, but it is also required for cats due to AE-damage. Expertise, hit and crit benefit cat form the most, but they are also significant threat increases for bears. Druids could conceivably be able to shift from DPS to tanking on the fly, with only a minimal loss in viability. Assuming they have optimized gear for one role, they will not be equal to a full role in the other, but they are by far the best alternative.

With the current changes, druids can look forward to WotLK with ease in their minds. Things are looking good. Let's hope things do not change too much during beta.

I am not 100% certain of the crushing blow change. As far as I know, it won't be a boss ability anymore, except maybe for specific bosses? Paladins would be their designated tanks, as they are now the only class that can become reliably uncrushable.

At the brink of danger I stand. Clad in armour, shield and sword in hand.

I realize you're just copying and pasting the article, Heart, but if the one for Protection Paladins is correct, Crushing Blows are being bumped up a level (from +3 to +4), meaning that raid bosses will no longer crush under normal circumstances.

Could be. A lot of the speculation regarding crushing blows has come from changes to tank talents/mechanics. I don't think that anyone is certain just yet. Do you recall where the reference was to the +4 level difference for crushing blows?

-Heart

At the brink of danger I stand. Clad in armour, shield and sword in hand.

Huh, it seems unlikely. Per the article you quoted (my link), it seems that Blizzard may always have been ambivalent about using Crushing Blows in boss fights. CBs were originally meant to keep players from grinding mobs too high above their level - the use of +3 level bosses took advantage of this mechanic by inheritance. The trouble is that it puts a serious cap on how much melee DPS a boss can be designed with. Fights like Azgalor and Archimonde would be impossible if those bosses could crush, as they could 2-shot a tank without even the slightest possibility of a healer save. What Blizzard did, of course, was remove the CB mechanic from those bosses, which leads to the question of why they didn't just remove it entirely and adjust boss DPS to match.

Crushing Blows have also been responsible for forcing certain gearing choices on tanks; not only do they have to reach the Defense cap, but there's always been that "hidden" 102.4% avoidance goal - if you are not aware of this mechanic (and there's no way to learn it without being told), you're at a disadvantage when gearing for endgame raiding. CBs make Druid tanking very problematic, effectively negating their inherent advantages for all but gimmick fights. Lastly, Death Knight tanking would have been nearly impossible as they are currently designed, had CBs been retained.

Edit: Here's one thought: If Blizzard does want to have gimmick boss fights where sudden spike damage is a concern, all they have to do is have the boss use the Unbalancing Strike ability. This was introduced with the Twin Emperor Vek'nilash (our realm's namesake) in AQ40 and is also used by Instructor Razuvious in Naxx. It inflicts ~2X weapon damage and reduces the target's Defense by 100 for a short duration. This greatly increases the chance of crits on the target, although it still won't affect CBs for Paladin/Warrior/Death Knight tanks. While the current edition of Razuvious is a "gimmick" fight in that it requires the use of MC'd mobs to tank him, the 10-man version won't be able to count on this and will probably have him using UBS on a traditional tank.

In the next data push, you will find Omen of Clarity has been changed a bit. The 10 second cooldown has been removed, the procs per minute has been raised from 2 to 3.5, and melee abilities no longer trigger it. Spell interaction with Omen of Clarity remains relatively unchanged, with its hidden chance to trigger off spells reduced by half (and rolling the dice about 2x as often).

What this means is that more auto-attacks landing on the target will increase the benefit from Omen of Clarity. Haste, increased hit chance, and expertise will all make Omen of Clarity better.

We are aware of the concerns with reaching the hit rating cap, and will make sure Druids can pick up Rogue items to wear without exceeding that cap. This means Rogues will likely socket for hit, while Druids socket for Strength or Agility.

Before LK goes live, we will do extensive testing on how much damage classes do, and will increase or decrease their power as appropriate to meet our targets. Cat raid DPS suffered relative to other melee in BC for lack of an Combat Potency equivalent talent (OOC should now be roughly equal), for lack of a scaling finishing move (Savage Roar answers that), for lack of benefitting from Windfury Totem, and for lack of weapon procs (+35 agility != Mongoose). All of those lacks have been addressed. In addition, a change has been made to make the agility rebalance less severe (as I posted in another thread).

In PvP, we are adding many tools to the Feral Druid arsenal, including the redesigned Maim, Infected Wounds, King of the Jungle, and Berserk. We have also made some improvements to the "range bug". Attacks that require you to be behind a target will no longer be able to be parried, nor able to be dodged by a player. Our movement engine will now smoothly interpolate positions of moving units, preventing the "Out of range/You must be behind your target/Out of range/You must be behind your target/Out of range/You must be behind your target..." sequence from occuring any more. In addition, being able to apply a snare makes the Feral Druid able to slow down their target and lessen the severity of the "range bug". Yes, there are still issues with the model, especially when switching into and out of cat form, but many of the issues are being dealt with.

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To help deal with this issue, in the next data push, Druids should find their melee critical strike chance is about 5% higher.

The conversion of agility to critical strike chance remains the same 40:1 at level 70, but the base amount for 0 agility has been increased by 5%.